1. Field of the Invention
The present invention relates to a grommet for fastening to a hatchback-type car body, and more particularly, to a grommet providing for passage of wires therethrough, the grommet configured for installation between an automobile roof and a rear door glass panel of a hatchback-type automobile, in which the glass panel is opened and shut independently of the rear door.
2. Description of Background Information Grommets providing for passage of wires are well-known in the related art. FIGS. 9 to 11 refer to such a related art grommet 5. The grommet 5 allows electric wiring to pass therethrough to a rear door of a hatchback-type automobile. The grommet 5 has cone-type diameter-expanding parts 5b and 5c on opposed ends of a small diameter tubular part 5a through which a group of electric wires is passed.
One diameter-expanding part 5b of the grommet 5 is affixed to a through-hole 1a formed at the edge of a roof panel 1 of a car body. The other diameter-expanding part 5c is affixed to a through-hole 3a formed by a hole in a rear door frame 3. A group of electric wires W is wired in a door from the through-hole 3a of the rear door frame 3 through the small diameter tubular part 5a of the grommet 5 and from the through-hole 1a of the roof panel 1, as shown in FIG. 11.
Hatchback-type automobiles having a glass panel in the rear door, where the glass panel may be opened and closed independently of the opening and closing of the entire rear door, have been recently introduced to the art. As shown in FIGS. 12 and 13, a rear door frame has a double structure in such a hatchback-type automobile, where a group of electric wires W is separately wired from a through-hole 1a of the roof panel 1 into both a through-hole 3a formed on the rear door frame 3 and a through-hole 40a formed on a frame 40 retaining a rear door glass panel 4.
In such a case, respective grommets 6A, 6B and 6C are respectively installed in the through-hole of a roof panel 1, in the though-hole 3a of rear door frame 3, and in the through-hole 40a of the glass retention frame 40, as shown in FIG. 13. However, water passing between electric wires of the group of electric wires W may enter into the roof or the inside of the rear door (inside of the frame), because the group of electric wires W is not covered with the grommet in the weather-exposed area between the rear door frame 3 and the glass retention frame 40. Therefore, a water-resistant agent such as a curing resin or the like is filled between electric wires of the group of electric wires W at the opening parts of the grommets 6A, 6B and 6C.
However, one problem with providing a water resistant agent is that construction is troublesome and high in cost. Additionally, the weather-exposed area is visible, and is thus unattractive because the group of electric wires W is in open view.
For the problems described above, the present inventor has previously provided the grommets 7 and 8 shown in FIGS. 14(A) and 14(B), which are described in Japanese Unexamined Patent Publication No. 9-150759. The grommet 7 shown in FIG. 14(A) is unitarily molded and has two tubular parts 7b and 7c that are perpendicular to an edge of tubular part 7a. For the grommet 8 shown in FIG. 14(B), tubular parts 8b and 8c are molded separately from tubular part 8a, and connected through joint tubes 8d and 8e to provide freedom of fastening and removal.
When the devices shown in FIGS. 14(A) and 14(B) are used, a group of electric wires in a water-exposed area may be kept water proof by being passed through the grommets 7 and 8. However, since both of the grommets 7 and 8 are molded with an flexible member comprising a rubber or an elastomer, the grommets 7 and 8 are deformed by the stiffness of the group of electric wires passed therethrough, at a position shown by dotted lines in FIG. 15. When such deformation occurs, there is a problem with maintaining water resistance, because the grommets contact other parts of the vehicle, thereby resulting in damages to the grommets.
As shown in FIG. 16, the electric wires often do not bend along with the contours of the grommets and the directions of the electric wires are uncontrolled even though electric wires are purportedly guided by bending the shape of the grommets, as the group of electric wires are stiff. Additionally, there is often only a flat space between the roof and rear door, thereby making wiring difficult, as wire groups are often too thick to pass therethrough.
Further, as the grommets 7 and 8 of FIGS. 14(A) and 14(B) are long in length, they are difficult to mold, and the passage of the group of electric wires is difficult. Particularly, there is a problem that molding is difficult. Also, insertion and passing a group of electric wires through the molded grommet cannot be easily carried out, since the grommet 7 has a plurality of bends.